Cold emails often land in spam folders due to issues like poor technical setup, spammy content, or a bad sender reputation. Here’s a quick summary of why this happens and how to fix it:
| Factor | Shared IP Pool | Dedicated IP |
|---|---|---|
| Cost | $2.49–$15/month | $99+/month |
| Setup | Immediate use | Requires warm-up |
| Control | Limited | Complete |
| Best for | Low-volume senders | High-volume senders |
| Risk | Affected by others | Dependent on your actions |
The technical setup of your email campaigns is the backbone of your deliverability. If it's not done right, your emails might end up in spam folders instead of inboxes. Email authentication is the key to proving you're a legitimate sender - it’s like showing your ID at the door.
"Email authentication is built on SPF, DKIM, & DMARC. These technical, essential terms will help you master email authentication and maintain brand reputation." - Higher Logic
Addressing these technical aspects is crucial to ensure your cold emails don’t get flagged as spam. Let’s break down the core components of email authentication and how to set them up correctly.
SPF (Sender Policy Framework) is like a whitelist for your domain. It tells receiving email servers which IP addresses are authorized to send emails on your behalf. When your email lands in someone’s inbox, their server checks your SPF record to confirm you’re allowed to use that domain.
DKIM (DomainKeys Identified Mail) adds a digital signature to your emails. Think of it as a tamper-proof seal that ensures your message hasn’t been altered during transit.
DMARC (Domain-based Message Authentication, Reporting, and Conformance) is the enforcer. It tells receiving servers what to do if SPF or DKIM fail - whether to deliver, quarantine, or reject the email altogether.
These protocols work together to protect your domain from spoofing and phishing attacks. DMARC relies on SPF and DKIM results to decide whether your email gets delivered. Yet, despite its importance, 75% to 80% of domains with a DMARC record still struggle to fully enforce it.
Here’s how to get started:
v=spf1 include:_spf.google.com ~all
"A full DMARC implementation prevents your emails from being spoofed and improves email deliverability." - DMARCLY
Sending emails from unverified domains is a recipe for trouble. Spam filters are quick to flag messages from unverified sources, especially since 83% of email delivery problems stem from sender reputation issues. In fact, 20% of legitimate emails never make it to the inbox due to poor sender reputation.
Without authentication, email providers can’t confirm that you’re the rightful owner of the domain. This weakens the protective framework established by SPF, DKIM, and DMARC.
"Email reputation refers to the overall perception of your email sending practices by internet service providers (ISPs) and email recipients. It is a measure of how trustworthy and legitimate your emails are perceived to be." - Carlos Ascanio
High bounce rates can hurt your reputation even further. When emails are sent to invalid addresses, ISPs see this as a sign of poor list hygiene or spammy behavior, damaging your domain’s credibility.
To fix this, implement a double opt-in process for collecting email addresses and use validation tools to verify them before sending. Services like MXToolbox can help you confirm that your SPF, DKIM, and DMARC records are set up correctly. Regularly cleaning your email list and monitoring bounce rates are also critical for keeping your deliverability on track.
Your IP address plays a major role in email deliverability. You have two choices: use a shared IP pool or invest in a dedicated IP.
Shared IP pools are great for smaller senders. They’re affordable (usually $2.49 to $15 per month) and require no warm-up period since the IP already has a reputation. This can benefit new senders who don’t yet have their own track record. But there’s a catch - if others sharing the IP engage in bad practices, like sending spam, it can hurt your deliverability.
Dedicated IPs, on the other hand, offer full control over your sender reputation. They’re ideal for high-volume senders with consistent sending patterns and good practices. The downside? They’re more expensive (starting at $99 per month with providers like Infraforge) and require a warm-up period to establish their reputation.
Here’s a quick comparison:
| Factor | Shared IP Pool | Dedicated IP |
|---|---|---|
| Cost | $2.49–$15/month | $99+/month |
| Setup | Immediate use | Requires warm-up |
| Control | Limited | Complete |
| Best for | Low-volume senders | High-volume senders |
| Risk | Affected by others | Dependent on your actions |
For smaller senders, shared IPs are often sufficient. But as your email volume increases and your practices stabilize, switching to a dedicated IP can give you greater control over your deliverability.
No matter which option you choose, maintaining proper email authentication (SPF, DKIM, DMARC) and keeping your email lists clean are non-negotiable for successful email campaigns.
Even with a flawless technical setup, the quality of your email content plays a huge role in determining whether your message reaches the inbox or ends up in the spam folder. With 160 billion spam emails sent daily and nearly one in five emails flagged by spam filters , crafting high-quality, professional content is more important than ever.
Modern spam filters go beyond looking for specific words - they assess sender reputation, engagement levels, and email structure. This means your emails need to appear polished and genuine.
"Spam filters nowadays are beginning to pay more attention not just to specific spam words as might have been the case previously but also to the overall reputation of the sender and the engagement generated by email recipients." - Yaroslav, Deliverability Expert at Mailtrap
To avoid spam traps, it’s essential to understand what triggers these filters and how to structure your emails effectively. Let’s dive into key strategies to keep your content spam-free.
Spam trigger words are certain terms or phrases that email providers associate with scams, overly aggressive sales tactics, or unrealistic promises. While you don’t need to eliminate these words entirely, it’s critical to use them sparingly and in the right context. For example, a subject line like "FREE MONEY!!! ACT NOW!!!" is a red flag, but "We’re offering a free consultation to discuss your marketing strategy" uses "free" in a professional and natural way.
Here are some tips to avoid content-related spam issues:
The structure of your email’s HTML and CSS can also set off spam filters. Disorganized or poorly written code can make your email appear untrustworthy, even if the content is solid. To ensure your emails display correctly across devices and platforms, stick to clean, simple coding practices.
Because email design still relies on tables for layout, prioritize basic CSS properties like font size, color, and background color. Always use inline styles instead of external stylesheets.
"When creating emails with HTML and CSS, prioritize compatibility over creativity. Test rigorously to ensure that your design looks great across all major email clients and devices!" - Daniel Schwarz, Designer, writer, mentor
For better delivery rates, follow these technical guidelines:
target="_blank" attribute to all links.Tools like Litmus can help you test your email designs and ensure they meet technical requirements.
Legal compliance is just as important as technical and content considerations when it comes to avoiding spam filters. The CAN-SPAM Act outlines federal rules for commercial email and protects recipients by giving them the right to opt out of future emails. Non-compliance can lead to fines of up to $53,088 per email.
This law applies to all commercial messages, including business-to-business emails. According to the FTC, a commercial message is any email primarily intended to advertise or promote a product or service.
Here’s how to stay compliant:
While European regulations require recipients to opt in before receiving emails, the CAN-SPAM Act focuses on providing a clear opt-out option. Ignoring these rules can harm your sender reputation and make it more likely that your emails will be flagged as spam. Email providers actively monitor compliance with these laws to protect users from unwanted messages.
Think of your domain reputation as your email’s version of a credit score. It reflects how mailbox providers perceive the trustworthiness and reliability of your branded domain. This reputation plays a huge role in determining whether your emails land in inboxes or get banished to spam folders.
Here’s why it matters: 77% of email deliverability issues are tied to poor domain reputation. According to Validity, many emails never even make it to the inbox, and when they’re flagged as spam, the costs can add up quickly.
Your domain reputation doesn’t just impact where your emails land - it also affects everything tied to your email identity, like your From Address, Return-Path Domain, DKIM signing domain, and even the links or branded assets in your messages. And while technical issues can often be fixed relatively quickly, repairing a damaged reputation takes time and consistent effort. Let’s dive into how you can build and safeguard this essential aspect of your email strategy.
Warming up a domain is all about gradually increasing your email volume to build a positive sender reputation with internet service providers (ISPs). This process typically takes a few weeks and starts with small, focused email sends to establish trust. Begin by sending 50–100 emails per major provider (like Gmail, Yahoo, or Outlook) to your most engaged recipients - those who are most likely to open, click, or respond. Then, slowly ramp up your volume, doubling every couple of days at first and later increasing by 20–50% as things progress.
Engagement is key during this warm-up phase. High engagement signals to email providers that your messages are worth delivering. To protect your primary domain’s reputation, consider using subdomains to separate different types of emails.
If you’re looking to speed up the process, services like Infraforge offer pre-warmed domains and automated DNS setups. Starting with an already-established reputation can help you avoid spam filtering right out of the gate.
Keeping an eye on your email performance metrics is non-negotiable when it comes to maintaining a strong domain reputation. Email providers closely monitor bounce rates, engagement levels, and spam complaint rates to decide how they treat your messages.
"It's a measurement of your email-sending practices and how closely you follow standards set by different servers/mailbox providers such as Gmail, Yahoo, Hotmail, Outlook, etc." - Olivia Carden, Product Manager at Cognism
Regularly tracking these metrics by provider can help you pinpoint issues. For example, if Gmail accepts your emails but Yahoo flags them as spam, you may need to adjust your approach for Yahoo recipients. Keeping a close watch on these numbers ensures that you can address problems before they escalate into reputation-damaging issues.
Once you’ve built a solid reputation, the next challenge is managing email volume increases without triggering spam filters. Sudden spikes in email volume can alarm providers, leading to deliverability issues. ISPs prefer consistent sending patterns, so gradual increases are the way to go.
For instance, if your typical daily volume is 1,000 emails, avoid jumping to 5,000 overnight. Instead, scale up step-by-step over several weeks. If you’re planning a big campaign, like a product launch or holiday promotion, give yourself enough lead time to gradually increase your sending volume without raising red flags.
Keep a close eye on your metrics during this period. If you notice a drop in open rates, a rise in bounce rates, or more spam complaints, pause your volume increase and investigate. Sometimes, sticking to a steady volume with good engagement is better than risking your inbox placement by scaling too fast.
For businesses with aggressive scaling needs, dedicated IP addresses can provide more control over your sending reputation. While shared IPs benefit from the collective reputation of multiple senders, they also expose you to the actions of others. Dedicated IPs require a careful warm-up process but allow you to fully manage your reputation.
Services like Infraforge offer tools like multi-IP provisioning and real-time monitoring to help you scale safely. With the right infrastructure and a systematic approach, you can increase your email volume without compromising deliverability or risking your domain reputation.
When it comes to cold email campaigns, ensuring your emails land in the inbox rather than the spam folder is a challenge. Diagnostic and optimization tools can help bridge that gap. By building on proper authentication and reputation practices, these tools provide practical, real-time solutions to keep your deliverability rates high.
Setting up SPF, DKIM, and DMARC manually can feel like navigating a maze - it’s tricky and prone to errors. Automated DNS setup tools simplify this process and help reduce misconfigurations.
These tools also help address technical hurdles, such as avoiding the SPF lookup limit of 10 by flattening SPF records to remain compliant.
IP rotation is a game-changer for cold email campaigns. By spreading your email traffic across multiple IP addresses, it reduces the chances of any single IP being flagged as spam. This is especially crucial for maintaining a positive sender reputation.
Success stories highlight the importance of proper IP management. For instance, Shopify achieved a 99.5% delivery rate with a 91.3% inbox placement rate by using SendGrid's IP pool management. Similarly, Klaviyo maintained a 99.94% average delivery rate while sending around 10 billion emails monthly.
Once you’ve got your configurations and IP rotation in place, the next step is monitoring performance to ensure everything runs smoothly.
Real-time monitoring tools are essential for spotting deliverability issues before they escalate. They provide instant alerts for problems like bounce rate spikes, engagement drops, or spam complaints, allowing you to act quickly.
"Deliverability is more of an art than a science - the landscape is constantly changing." – Nonso Maduka, Director of Product Management at Glassdoor
Combining multiple monitoring strategies can make a big difference. For example, Glassdoor achieved a 99.5% average monthly delivery rate and kept its spam rate at an impressive 0.007% by using real-time monitoring alongside SendGrid's Email API and Expert Services team. Key metrics to keep an eye on include bounce rates (aim for under 2%), spam complaint rates (below 0.1%), and engagement rates. Monitoring these helps you adjust your strategy swiftly when needed.
Getting your cold emails into inboxes - not spam folders - requires a mix of technical setup, engaging content, and consistent oversight. With 23% of sales professionals identifying cold emails as the best way to reach prospects and 21% noting they generate the most leads, ensuring deliverability is a must for effective outreach.
Authenticate your emails properly. Start by setting up SPF, DKIM, and DMARC records. These protocols verify that your emails are sent from authorized sources, laying the groundwork for trustworthy communication. Without these, your emails are more likely to be flagged as spam.
Warm up your domain and IP gradually. Build credibility with email service providers by slowly increasing your sending volume over a period of four to eight weeks. Start with your most engaged recipients and maintain a consistent schedule. A sudden spike in email volume can raise red flags with mailbox providers, potentially leading to blocks or filtering.
Prioritize quality content and compliance. Subject lines matter - a lot. With 64% of people deciding to open emails based on the subject line and 33% more likely to open emails with catchy ones, crafting compelling, spam-free messages is key. Avoid spam trigger words, use clean HTML formatting, and always include an easy-to-find unsubscribe option to stay compliant with legal requirements.
Keep your email list clean. Purchased email lists might seem like a shortcut, but they can hurt your sender reputation. Instead, use double opt-in processes to ensure recipients genuinely want your emails. Regularly clean your list to remove inactive addresses and segment your audience for more personalized messaging. Tracie Pang, Email Marketing Manager at ThirdLove, offers a crucial reminder:
"There's this expectation that you always need to send an email. But if you're continuing to send emails without engagement, it's going to affect your sender reputation. Sending to your list multiple days in a row like that could lead to more than one spam complaint because they're tired of hearing from you."
Monitor results and use specialized tools. Keep an eye on metrics like bounce rates, spam complaints, and engagement levels. Tools like Google Postmaster Tools can help you track performance, while platforms like Infraforge offer features like real-time monitoring, dedicated IPs, and automated DNS setup. Infraforge users, for instance, can secure inbox placement rates of 85% or higher, with plans starting at $17 per month.
Each of these steps - from authentication to monitoring - plays a role in improving email deliverability. By combining solid technical settings with engaging, respectful communication, you can ensure your emails land where they’re meant to: in your recipients' inboxes.
To get the best results when warming up a dedicated IP and improving email deliverability, start by sending a small number of emails to your most engaged recipients - those who’ve recently interacted with your messages. Over the course of 4–8 weeks, gradually increase the volume of emails you send. This slow and steady approach allows your IP to build a strong reputation.
Keep a consistent sending schedule and pay close attention to key metrics like open rates, click-through rates, and bounce rates. Additionally, ensure that your email authentication protocols, such as DKIM and SPF, are correctly set up. These steps help build trust with email providers and reduce the risk of your emails ending up in spam folders.
When crafting cold emails, steer clear of trigger words that can catch the attention of spam filters. Words like free, urgent, limited time, act now, guaranteed, winner, cash bonus, best price, earn money, and discount are often linked to promotional or spammy content and can send your message straight to the spam folder.
Instead, focus on writing messages that are clear, professional, and genuinely helpful. Personalize your emails to show that you’ve put thought into the recipient, and avoid language that feels overly pushy or sales-driven. This approach not only helps you bypass spam filters but also increases the likelihood of engaging your audience.
The CAN-SPAM Act is a U.S. law designed to regulate commercial emails, including cold outreach, to shield recipients from spam and dishonest practices. Non-compliance can lead to penalties as steep as $53,088 per email. So, following the rules isn’t just about avoiding fines - it’s also about maintaining your reputation.
Here are the core rules for compliance:
Staying compliant doesn’t just protect you legally - it also helps build trust and engagement with your audience. To simplify the process, consider using tools that handle opt-outs and ensure your emails meet these standards.